This invention relates to automotive gas turbine engines, as shown for example in U.S. Pat. No. 4,038,815, issued on Aug. 2, 1977 to A. M. Heitmann et al. My invention relates especially to an improved turbine wheel construction for such engines, and to arrangements for selectively cooling portions of the turbine wheels to minimize thermal expansion effects that would tend to cause premature turbine wheel failure. I propose to form the turbine blades out of a temperature-resistant ceramic refractory material having high compressive strength but relatively low tensile strength; to prevent explosive failures I confine the blades within a surrounding annular band formed of stainless steel or other high tensile strength material. I avoid undesired expansion of the high tensile strength band relative to the refractory blades by selectively cooling the band outer surface.
My invention has for its object the provision of a hot gas turbine wheel having performance capabilities at temperatures in excess of 2,000.degree. F. and relatively high velocities, e.g. in excess of 30,000 r.p.m.